Blowers are commonly used air delivery devices which usually includes a motor to drive an impeller connected to the motor. The impeller in turn drives the air to generate an airflow. The motor generally includes a stator and a rotor rotatable about the stator. The rotor is connected to the impeller and hence drives the impeller to rotate to thereby drive the airflow. In order to reduce cost, single-phase motors have been used to drive the blower. However, a series disadvantage of a typical single-phase motor is that the rotor of the motor can easily stop at a dead-point position, which would result in startup failure of the motor. In order to deviate the stop position of the rotor from the dead-point position, teeth of the stator are usually configured to have unsymmetrical outer surfaces in the art. However, such motor configured has a very large cogging torque, which causes torque fluctuation and hence vibrations and noises of the motor.